<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        article{
            width: 500px;
            height: 200px;
            background-color: #ccc;
            margin:0 auto;
        }
        article>div.left{
            width: 100px;
            height: 200px;
            background-color: red;
            float: left;
        }
        article>div.right{
            width: 100px;
            height: 200px;
            background-color: blue;
            float:right;
        }
        article>div.center{
            /* width: 100%; */
            height: 200px;
            background-color: orange;
            margin-left: 100px;
            margin-right: 100px;
        }
    </style>
</head>
<body>
    <article>
        <div class="left"></div>
        <div class="right"></div>
        <div class="center"></div>
        <!-- <div class="right"></div> -->
    </article>
</body>
</html>